The present invention relates to a sensor assembly for motor vehicle steering systems, having a torque sensor for magnetically determining a steering torque.
It is common practice nowadays to install sensors into motor vehicle steering systems for determining the steering torque and/or the steering angle, in order to allow steering assist means to be driven, for example.
In connection with the development of electric steering systems, a reliable provision of sensor data about the steering angle and steering torques becomes increasingly more important.
In addition to the fundamental goal of ensuring a high failure safety of the sensor system and therefore of the respective steering system, efforts are also made to design the necessary sensors such as to make them as compact and low-cost as possible, because of cramped spatial conditions in the region of the steering.
DE 602 00 499 T2 and corresponding U.S. Pat. No. 7,028,545 B2, both of which are incorporated by reference herein in entirety, for example, describes a fairly compact position sensor for detecting rotation of a steering column, in which the angles measured are on the order of about 10 degrees and are used for capturing a torque. To determine the torque, merely a tubular magnet yoke is required here, which has a plurality of magnets attached in pairs to the radial outside thereof.
Apart from information relating to the steering torque, information relating to the current steering angle, in particular relating to the absolute steering angle, is also of major importance in vehicle steering systems. Rotary encoders are already described in the prior art which assign a unique encoded positional value to each angular position, so that the absolute rotational angle is also known for a turn of the steering wheel of more than 360 degrees.